$re = '/^((?!\bsrc\b).)*src="([^"]+)/';
$str = '<img src="http://ia.media-imdb.com/images/M/MV5BMTY3NjY0MTQ0Nl5BMl5BanBnXkFtZTcwMzQ2MTc0Mw@@._V1_SY317_CR0,0,214,317_AL_.jpg" />
<img src="http://ia.media-imdb.com/images/M/MV5BMjAzODk4OTI3Ml5BMl5BanBnXkFtZTgwMzU2MTY0MzE@._V1_SX86_CR0,0,86,86_AL_.jpg" />
<img src="http://ia.media-imdb.com/images/M/MV5BNzUzNzY1NzQxM15BMl5BanBnXkFtZTgwMTM0MTY0MzE@._V1_SY86_CR33,0,86,86_AL_.jpg" />
<img src="http://ia.media-imdb.com/images/M/MV5BMTAxNTAwMTg0ODReQTJeQWpwZ15BbWU4MDMzNDE2NDMx._V1_SY86_CR33,0,86,86_AL_.jpg" />';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php